Eating Up RO Membranes

[flyfisher2]

what is the water pressure to the RO unit?

60

 

[laverda]

OKay, so taking everything into consideration I'm thinking of just replacing the present RO/DI which is about 7 years old, with a 5 stage unit that I'll install inside. Are there major differences between these units or is it all based on the membrane quality and filter cartridges used?

Everything is based on the filters and membrane myour using. My system is 20 plus years old. I don't think replacing your RODI is going to change a thing in the long run. You will probably ruin you membrane even faster if you replace it with the one you describe. Your system with multiple pre-filter,carbon filters and DI canisters is a much better set up then the new one your considering.

Did you ever test for chlorine and chlorimines with a good quality test kit?
Something is clearly destroying you membranes. You might talk to the membrane manufacturer to see what else could be the issue besides heat and chlorine.

 

[flyfisher2]

I agree that I liked my system but It has been exposed to the elements and two canisters have leaks. I’ve gone through several membranes and no improvement.
I’ll start from scratch and see if I have the same issue
I’m tired of throwing my luck and money at guessing
Lots of variables with my system
If problem continues then I’ll combine all into a 12 Stage Turbo charged RO/DI

 

[flyfisher2]

Everything is based on the filters and membrane myour using. My system is 20 plus years old. I don't think replacing your RODI is going to change a thing in the long run. You will probably ruin you membrane even faster if you replace it with the one you describe. Your system with multiple pre-filter,carbon filters and DI canisters is a much better set up then the new one your considering.

Did you ever test for chlorine and chlorimines with a good quality test kit?
Something is clearly destroying you membranes. You might talk to the membrane manufacturer to see what else could be the issue besides heat and chlorine.

Is the membrane in fact destroyed?
We see no holes or visible damage.
How’d we know for sure?

 

[sunken3]

Pool strips arent the most accurate thing (think API test kits) but they can give you a ballpark.

true.. but if they show positive you likely have found your issue.

 

[sunken3]

not sure this was covered (by page five I started scanning posts).. but another issue could be your auto-stop valve. most folks have their waste water plumbed to a sewer line and would never know if the water was constantly "leaking".. that could be pushing low pressure water through your membrane constantly killing it. then of course your DI gets eaten when you actually make water.

 

[flyfisher2]

what is the water pressure to the RO unit?

60

 

[flyfisher2]

not sure this was covered (by page five I started scanning posts).. but another issue could be your auto-stop valve. most folks have their waste water plumbed to a sewer line and would never know if the water was constantly "leaking".. that could be pushing low pressure water through your membrane constantly killing it. then of course your DI gets eaten when you actually make water.

I shut the valve off at the hose bib because it's a three way and I have the hose connected as well.

 

[Woodyman]

I agree that I liked my system but It has been exposed to the elements and two canisters have leaks. I’ve gone through several membranes and no improvement.
I’ll start from scratch and see if I have the same issue
I’m tired of throwing my luck and money at guessing
Lots of variables with my system
If problem continues then I’ll combine all into a 12 Stage Turbo charged RO/DI

I shut the valve off at the hose bib because it's a three way and I have the hose connected as well.

I've changed my vote to 12 stage turbo DI!!!

 

[Woodyman]

In all seriousness though, if you can salvage and make room for additional cartridges you should especially since you already have them. I would run at least 3 pre-filters, a double RO, and 3 DI, if you can't do the 3 DI I would say make 2 work at least.

 

[DrZoidburg]

not sure this was covered (by page five I started scanning posts).. but another issue could be your auto-stop valve. most folks have their waste water plumbed to a sewer line and would never know if the water was constantly "leaking".. that could be pushing low pressure water through your membrane constantly killing it. then of course your DI gets eaten when you actually make water.

That could be true too. I hate those aso valves. I have switched to solenoids because of that.

 

[DrZoidburg]

Free chlorine is a pretty aggressive chemical, and the hotter it is the more reactive. I cant say how often you would change them as Im not on city water but mine last about 2 years on well water. Hard water eats them up, high ph water, and leaky aso valves. Maybe the restrictor isn't the right size. Could also be it. Cant think of much else right now.

 

[flyfisher2]

In all seriousness though, if you can salvage and make room for additional cartridges you should especially since you already have them. I would run at least 3 pre-filters, a double RO, and 3 DI, if you can't do the 3 DI I would say make 2 work at least.

I will try. Just trying to find some wall space over the slop sink and washer and dryer. I already see I have to swap out the electrical outlet behind the washer. It's a single outlet and I'd need a double in order to accommodate the RO pump

 

[flyfisher2]

Free chlorine is a pretty aggressive chemical, and the hotter it is the more reactive. I cant say how often you would change them as Im not on city water but mine last about 2 years on well water. Hard water eats them up, high ph water, and leaky aso valves. Maybe the restrictor isn't the right size. Could also be it. Cant think of much else right now.

Thanks Doc, I appreciate your input. I double checked the restrictor and it's the right one for 75 gal membrane. Let's see what happens when I bring the new unit inside.

 

[flyfisher2]

Just wish I knew for sure what a damaged membrane looks like. I see no holes or physical damage. Would it be apparent?

 

[flyfisher2]

Well guess what came in the mail today?

 

[DrZoidburg]

You wouldn't be able to really see with naked eye. https://www.researchgate.net/figure...at-37-C-for-location-6-run-3-b_fig8_316106492 That chlorine level seems middle of the road at 1.7+/- . Reading epa regulation says they cant go above 4ppm. Also that you should get between 6 -12 months on one membrane. Around a hypothetical 9 months at your levels. If you checked all the other problem spots and nothing changes. One other thing I can think of is maybe run a big canister of anion resin before it enters the membrane.

 

[flyfisher2]

I was running anion ,cation and then the mixed. This lasted about three months based on my usage. I guess that's okay. I went through a mixed in 60 gallons yesterday. I'm thinking the cost would be very high and probably comparable to the cost of replacing the membrane or even higher?

 

[flyfisher2]

I was running anion ,cation and then the mixed. This lasted about three months based on my usage. I guess that's okay. I went through a mixed in 60 gallons yesterday. I'm thinking the cost would be very high and probably comparable to the cost of replacing the membrane or even higher?

You wouldn't be able to really see with naked eye. https://www.researchgate.net/figure...at-37-C-for-location-6-run-3-b_fig8_316106492 That chlorine level seems middle of the road at 1.7+/- . Reading epa regulation says they cant go above 4ppm. Also that you should get between 6 -12 months on one membrane. Around a hypothetical 9 months at your levels. If you checked all the other problem spots and nothing changes. One other thing I can think of is maybe run a big canister of anion resin before it enters the membrane.

I would love to hear from other Florida reefers and have them share their experience with this problem I'm having. Is it an isolated incident which would then rule out the chlorine issue and we would then assume the heat or faulty equipment.

 

[zalick]

I would love to hear from other Florida reefers and have them share their experience with this problem I'm having. Is it an isolated incident which would then rule out the chlorine issue and we would then assume the heat or faulty equipment.

I admittedly didn’t read all 8 pages….

your chlorine report doesn’t look bad IMO. Regular carbon blocks should take care of that. Always test for chlorine breakthrough as chlorine will destroy the RO membrane.

I have a Spectrapure maxcap 180gpd. I installed a big blue carbon after my sediment filters. I’ve processed around 15,000 gallons, producing 7,500 gallons of RO through the big blue and my two RO membranes. Rejection is still 99.99%.